Board logo

Sierra diff pinion seal, do I need a new crush washer?
flanders - 9/1/17 at 02:20 PM

I'm reading conflicting info on the site using the search function.

I'm going to replace the diff pinion oil seal, is the flange nut anything to do with pre-load etc? Or can u just undo the flange nut, replace the seal then torque the nut back up without worrying about a crush washer etc?

Also is the flange nut reversed or normal thread?

Cheers

CosKev3 - 9/1/17 at 03:52 PM

No

There is a inner nut that you use for setting up the diff,you just remove the drive flange nut and flange to change seal

Normal thread iirc

[Edited on 9/1/17 by CosKev3]

flanders - 9/1/17 at 04:03 PM

ah good man, THAT is the answer i was looking for, that means I can do it myself

CosKev3 - 9/1/17 at 04:09 PM

Has the diff been apart before?

Might need a good rattle gun to undo the nut

[Edited on 9/1/17 by CosKev3]

flanders - 9/1/17 at 04:12 PM

No idea mate, not by me anyway. its leaking oil quite badly, its just one of my million problems at the moment lol

colin99999 - 9/1/17 at 08:26 PM

An old school ex-Ford tech did my diff pinion seal and showed me what he was doing throughout the process.

He used a centre punch to dot the nut and flange, we changed the seal then did the nut back up to align the dots. Tightened back up to the same place to maintain the preload apparently.

old_timbo - 9/1/17 at 09:26 PM

quote:
Originally posted by colin99999
An old school ex-Ford tech did my diff pinion seal and showed me what he was doing throughout the process.

He used a centre punch to dot the nut and flange, we changed the seal then did the nut back up to align the dots. Tightened back up to the same place to maintain the preload apparently.


I changed my diff seal and did the more or less the same by marking the flange, nut and shaft with a paint pen. It worked out fine in the end. However the flange nut is really tight and due to the spring in the drive shafts etc I ended up having to drop the diff. out of the car to get it on the bench. I drilled a couple of holes in a length of angle that I could bolt to the flange to stop it turning while I used a rattle gun on it. Digging the old seal out was a bit of a monkey.... and then I discovered there are two diameters of seal and I had the wrong one. Naturally this was late on a Sunday afternoon!

CosKev3 - 9/1/17 at 10:50 PM

quote:
Originally posted by colin99999
An old school ex-Ford tech did my diff pinion seal and showed me what he was doing throughout the process.

He used a centre punch to dot the nut and flange, we changed the seal then did the nut back up to align the dots. Tightened back up to the same place to maintain the preload apparently.


The preload is done with the inner nut,the flange nut just holds the flange on and doesn't alter any diff settings

mark chandler - 9/1/17 at 10:57 PM

When I had mine apart I put in a 3.14 ratio which included moving over the pinion bearing.

I put the crush washer on a spike and dressed the bulge with a light hammer effectively growing it, then used this with a new seal.

When you install you keep tightening crushing the washer until you get a little preload on the bearing, this is not a lot, a couple lb/inch (not foot) on used bearings, so just tighten until it just starts to resist spinning the pinion with the crown wheel out. Put the crown wheel in then do the same with this out of mesh on the castellated nuts, now march the crown wheel into mesh moving both sides together until you have removed all the freeplay in the gear teeth the back out a smidge so runs freely with minimal backlash.

Assuming the gears and bearings have already done 100,000 miles so will need tightening up a tad.